﻿using System;
using System.Diagnostics;
using System.Windows.Input;

namespace Greenshot2Core.WPF.Command {
	public class RelayCommand : ICommand {
		#region Fields

		readonly Action<object> _execute;
		readonly Predicate<object> _canExecute;

		#endregion // Fields

		#region Constructors

		public RelayCommand(Action<object> execute)
			: this(execute, null) {
		}

		public RelayCommand(Action<object> execute, Predicate<object> canExecute) {
			if (execute == null) {
				throw new ArgumentNullException("execute");
			}

			_execute = execute;
			_canExecute = canExecute;
		}
		#endregion // Constructors

		#region ICommand Members

		[DebuggerStepThrough]
		public bool CanExecute(object parameter) {
			return _canExecute == null ? true : _canExecute(parameter);
		}

		public event EventHandler CanExecuteChanged {
			add {
				CommandManager.RequerySuggested += value;
			}
			remove {
				CommandManager.RequerySuggested -= value;
			}
		}

		public void Execute(object parameter) {
			_execute(parameter);
		}

		#endregion // ICommand Members
	}
}
